Tire Test - Kenda Juggernaut Pro

Test Summary

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The Kenda Juggernaut Pro is the lightest 26x4.00 sized fat bike tire you can buy. With a specified weight of just 835 grams, it's much lighter than most other fat bike tires. To achieve this exceptionally low weight, Kenda uses an ultralight 120 TPI casing covered with a minimal amount of rubber. The drawback of this light construction is clear: this definitely isn't the most durable or indestructible fat bike tire.

Next to the ultralight 120 TPI casing, the Juggernaut Pro also uses a dual tread compound with softer cornering knobs and harder center knobs for longer life. The folding beads are of the tubeless-ready kind which makes this tire easier to seal when used in a tubeless configuration. A cheaper 60 TPI wire bead version of the Juggernaut is available as well. Do keep in mind the 60 TPI version has a much higher weight of 1285 grams.

With such a low weight, it seems logical for this tire to also have an exceptionally low rolling resistance. Let's put this tire to the test and find out if that's true.

As previously mentioned, specified weight is 835 grams. My sample of the Juggernaut comes in at a slightly higher 853 grams. On a 65C rim, at an air pressure of 16 psi, the casing of the 26x4.00 Juggernaut has a width of 95 mm. The maximum height of the tire comes in at 84 mm.

With a height of 3 mm for both the center and edge knobs, the knobs on the Juggernaut are the smallest I've measured up to now. As expected for a tire with such a low weight, the sidewalls have a thickness of just 0.5 mm which is much less than most other fat bike tires. It must be said that most fast normal sized MTB tires have sidewalls that are just as thin as these.

Use the formula: RR (watts) = CRR * speed (m/s) * load (N) to calculate rolling resistance at a given speed and load

Low weight? Check! Low rolling resistance? No! Not at all. It's crazy, but the Juggernaut Pro actually has the highest rolling resistance of all fat bike tires I've tested to date. How can rolling resistance be so high when the tire is this light? To me, it's clear Kenda doesn't use materials that have been optimized to offer a low rolling resistance. Maybe they forgot to think about this or they simply don't care about the rolling resistance of their tires.

I can't imagine how high rolling resistance of the 60 TPI version of this tire will be. My machine probably can't even handle that tire as the 120 TPI Juggernaut was already stressing the machine to the max. At full power, at an air pressure of 8 psi / 0.6 bars, I was only able to spin this tire up to 195 rpm instead of the required 200 rpm, the machine simply didn't have enough power. I've added 2.5% to the 195 rpm measurement to calculate the 200 rpm (18 mph / 29 km/h) power.

Puncture Resistance Test Results

Puncture Resistance Test Result (higher is better)

Puncture Resistance Tread

7

Puncture Resistance Sidewall

4

As expected from such a light tire, puncture resistance isn't impressive. With a tread puncture score of 7 points, it performs average. The sidewall puncture score of 4 points is lower than average but expected from the very thin sidewalls.

Conclusion

The 120 TPI Kenda Juggernaut Pro is a fat bike tire with an extremely low weight. Unexpectedly, rolling resistance is extremely high and it's the reason I wouldn't touch this tire with a 10-foot pole. When compared to the Schwalbe Jumbo Jim LiteSkin (read review), at an air pressure of 8 psi, you'll lose close to 40 - 50 watts of power for a pair of tires. When you consider that the average cyclist can generate 250 watts, that's an insane amount of power lost in the tires.

I rate this tire 1 out of 5 based on my tests. I can't see a reason to fit these tires if they perform this bad in the tests, I give it the 1 point for its low weight. Check the overview page (overview) to see which tires I do recommend.